An order of battle (often abbreviated as ORBAT or OOB) is an organizational tool used by military intelligence to list and analyze enemy military units. In United States Army practice, an order of battle should relate what an American unit might be expected to encounter while on field operations. Orders of battle analyze enemy units, personnel, and equipment.

The United States Army breaks down an order of battle entry by the following factors:

• Composition: the command structure and organization of headquarters and subunits
• Disposition: geographical locations of unit headquarters and subunits
• Strength
• Training
• Tactics used by the enemy unit
• Logistics: how the enemy unit obtains its supplies
• Combat Effectiveness
• Electronic Technical Data
• Miscellaneous
  • Personalities
  • Unit history
  • Uniforms and insignia

The collection of order-of-battle data is the responsibility of the unit commander, through the G-2/S-2 (intelligence) section. An U.S. Army military intelligence group maintains an Order of Battle Section.

The rule of thumb used by American military intelligence is that each unit should follow enemy subunits two echelons down: that is, a division should monitor enemy battalion, a brigade should monitor enemy companies, and a battalion should monitor enemy platoons. General George S. Patton was one of the first to recommend this practice.

The term is also used by historians and war gamers to list the organization and unit structure of both sides in a battle.

See also

• List of orders of battle.